Controlled tension winding apparatus



June 15,1965 H. A. HALEY 3,139,295

CONTROLLED TENSION WINDING APPA ATUS Filed Nov. 23, 1962 2 Sheets-Sheet 1 HOR/ZO/VTAL June 15, 1965 H. A. HALEY CONTROLLED TENSION WINDING APPARATUS 2 Sheets-Sheet 2' Filed NOV. 23

HomzoA/rm United States Patent 3,189,295 CONTROLLED TENSION WINDING APYARATUS Harold A. Haley, Secane, Pa, assignor, by mesne assignments, to FMC Corporation, San Jose, Caiif., a corporation of Delaware Filed Nov. 23, 1962, Ser. No. 239,753 3 Claims. (Cl. 242-75.5)

This invention relates to an improved apparatus for controlling the tension on a strip which is being wound onto a roll.

While the invention probably has greatest value in connection with winding film or sheet material, it also has utility in winding strand material and in the appended claims and generally throughout the specification the term strip is employed to designate all types of articles capable of being or customarily wound into cylindrical packages or rolls.

When strip material is being wound onto a roll, it is usually either being fed toward the roll at a constant linear speed, as in the case of the original collection of the strip at the end of a processing or manufacturing operation, or is being withdrawn from another roll in a so-called rewinding operation. During the winding or rewinding, as the diameter of the winding roll increases, the peripheral speed thereof increases if the rpm. remains constant and this would normally result in a continually increasing tension in the strip. An increasing tension is usually undesirable and many provisions have been made to avoid it. In some rewinding operations, the winding roll is rotated at a constant rpm. and the supply roll is provided with a brake which is gradually released as the operation proceeds. At times it is practicable to maintain the rpm. of the winding roll constant and positively feed the strip thereto at a continually increasing speed. However, the simplest and most common way of preventing an increasing tension in the strip is by reducing the r.p.m. of the winding roll as the diameter thereof increases. The present invention will be described in connection with the latter type of operation, but it will become apparent that it is equally applicable to other means for controlling the tension.

In some winding operations it is desirable to maintain a constant tension in the strip. Others are most advantageously carried out by reducing or tapering the tension as the winding roll diameter increases. The degree of tension taper desired depends largely upon the nature of the material being wound. The present invention provides a simple apparatus for controlling the rpm. of a winding roll so as to provide either substantially uniform strip tension or a tension having any desired taper.

It is an object of this invention to provide an improved and simplified apparatus for controlling the tension in a strip which is being wound into a roll.

A further object of the invention is to provide a controlled tension winding apparatus which, by merely relocating one of the elements thereof, may be caused to produce a substantially constant strip tension or any desired tension variation.

Other objects, features and advantages of the invention will become apparent as the detailed description of a preferred embodiment thereof proceeds.

Referring now to the drawings:

FIG. 1 is a diagrammatic View showing the geometric arrangement of certain essential elements of the apparatus; FIG. 2 is an elevational view showing the manner of mounting a guide roller over which the strip passes as it approaches the wind-up roll;

FIG. 3 is an end view showing the manner of adjusting the position of the guide roller;

. sion is constant.

3,189,295 Patented June 15, 1965 lCC FIG. 4 is a diagrammatic view showing the means for controlling the speed of the Wind-up roll;

FIG. 5 is a graphic representation of the strip tension produced when the guide roller is in a first position; and

FIG. 6 is a graphic representation of the strip tension produced when the guide roller is located in a different position.

The present invention depends upon the location of various elements and the forces involved due to these locations. The actual structure of the elements and the mounting of the same may be entirely conventional and may take a variety of forms and for this reason such details have in the main not been shown.

Referring to FIG. 1, a strip 10 is supplied from a processing operation at a substantially constant rate. The strip is directed about a roller or guide 11, preferably freely rotatable on an axis 12, and thence about another guide preferably in the form of a roller 13 freely rotatable on an axis 14. From roller 13, the strip proceeds to a wind-up reel, drum or core 15 rotatable by means of a variable speed electric motor 16 see FIG. 4, about an axis 17. As shown in FIG. 2, guide roller 13 is carried by a pair of arms 18 and 19 secured to a shaft 20 which, as will presently be explained, may be fixed in a plurality of rotated positions. In FIG. 1 the center line of arm 19 is indicated and the axis of shaft 20 is designated 20. By swinging arm 19 and its mate 18 about the axis 20, roller 13 may be located in a variety of positions, two of which are shown in dotted lines.

As shown in FIG. 1 when arm 19 is in the vertical position shown in full, the top of roller 13 is horizontally aligned with the bottom of roller 11 and at the beginning of the winding operation the strip 10 moves vertically from roller 13 to the empty reel 15. As the strip builds up on the reel, as indicated in chain dotted lines, the included angle between the line of approach of the strip material to guide 13 and the line of movement of the material away from the guide grows progressively smaller. It will be apparent that this decreasing angle occurs irrespective of the swung position of roller 13 about the axis 20', although the actual value or degree of the angle for any particular diameter of the windup roll will depend upon the position of guide roll 13.

Considering first the conditions that prevail when guide roll supporting arm 19 is vertical and referring to the graph of FIG. 5, it will be noted that at the start of the operation the tension in the strip produces a horizontal force and a vertical force on the arm 19 at the axis 14 of roll 13, these horizontal and vertical forces being represented by the lines 21 and 22 respectively. These vertical and horizontal forces are, of course, of equal magnitude and produce a resultant force acting at 45 between them. As the diameter of the wind-up roll increases, the angle between the line of approach of the strip to guide roller 13, as represented by line 21, and the line of movement of the strip away from the guide, as represented by line 22, decreases as aforesaid and in FIG. 5, the directions of the force produced by the strip tension between guide 13 and the wind-up roll are indicated in full lines emanating from point 14 and if the tension remained of constant magnitude these lines would terminate where indicated by heavy dots; that is, on an arc of a circle whose center. is at roll axis 14. The resultants of the two forces acting on roller 13 are shown in dash lines and if the strip tension remained constant these resultant forces would terminate where indicated by small circles. It will be apparent that the resultant forces, as the wind-up roll increases in diameter have horizontal components of increasing magnitude when the strip ten- Thus, with constant strip tension there is a constantly increasing force perpendicular to arm 19 tending to move roller 13 in a particular direction, namely clockwise about the axis 20.

According to the present invention and in a manner to be explained, the strip tension is maintained at the level necessary to produce a constant force perpendicular to arm 19. When arm 1? is vertical, the force component perpendicular to the arm at the start of the operation is the same as the tension represented by line 21 and if this component is to be maintained constant the resultant forces represented by the dash lines must terminate at line y, said line being parallel to the line representing arm 19 and extending perpendicularly through the end of line 21. The resultant force lines are provided with arrows where they cross line y and by drawing horizontal lines from the arrows to the components representing the tension in the strip as it moves toward the wind-up roll, the amount or value of the tension necessary to produce resultants of the required magnitude may be ascertained. In FIG. 5 the magnitude of the tension as the wind-up roll increases in diameter is represented by the distance from the small xs to axis 14 and it will be observed that the tension decreases substantially as the wind-up roll diameter builds up.

FIG. 6 represents graphically the forces involved when arm 19 is displaced 60 clockwise from the horizontal line through axis 20'. In this figure, the line of approach of the strip material toward roller 13 is designated by the line 23 and the length of said line represents the starting tension. It will be observed that line 23 is not horizontal because in swinging about axis 20', axis 14 or roller 13 moves upward. The line of movement of the strip ma terial away from roller 13 at the beginning of the winding operation is designated by line 24 and the length of said line also represents the starting tension. The light solid lines emanating from point 14 show the various directions of movement of the strip between roller 13 and the wind-up roll as the latter increases in diameter. If the strip tension remained constant, the light solid lines, the length of which represent tension, would terminate where indicated by heavy dots, that is on an arc of a circle whose center is at 14. The resultants of the tension forces are indicated by dash lines and if the tension remained constant these resultants would terminate where indicated by small circles. The first resultant, that is the resultant of the forces represented by lines 23 and 24, has a component perpendicular to arm 19, the magnitude of which may be ascertained by drawing a line x through the end of said resultant parallel to arm 19 and measuring the perpendicular distance between line x and line 12. If the resultants are to have components perpendicular to arm 19 of this same magnitude, they must terminate at line x and such terminals are indicated in FIG. 6 by the small arrows. When lines are drawn through the arrow terminals of the resultant force lines parallel to line 23, they will cut the lines representing the direction of movement of the strip toward the wind-up roll at the points indicated by small xs. The magnitude of the tension is represented by the distance from the small xs to axis 14. It will be observed that with arm 19 located at the 60 angle the strip tension necessary to maintain constant the force perpendicular to said arm also decreases as the wind-up roll diameter builds up, but that the decreasing tension is not as pronounced as in the case where arm 19 is displaced 90 from the horizontal.

Obviously, similar graphs may be drawn to show the strip tension necessary to maintain constant the force perpendicular to arm 19 for any given position of said arm. These strip tension values can also be ascertained by the use of a computer and it is believed to be apparent that the actual values depend upon the geometry of the parts shown in FIG. 1. For the moment, it is suffice to note that the less the angle, measured clockwise, between arm 19 and the horizontal through axis 20', the less the tension must be dropped to maintain constant the force perpendicular to the arm and that by properly positioning said arm a substantially constant strip tension will provide a constant force perpendicular to the arm.

By way of an illustrated example, the apparatus diagrammatically illustrated in FIG 1 has been worked out in connection with the winding of cellophane film and the following tables show film tensions necessary to provide a constant force perpendicular to arm 19 when the parts have the following dimensions: Length of arm 19 from axis 14 to axis 20:l0"; diameter of roller 11:4.375"; diameter of roller 13 4.375"; radius of core or reel 15: 4.25"; distance from axis 20 to axis 1=l5.15; distance from axis 20 to axis 17:27.4"; distance from axis 12 to axis 17:29.35. In each instance, the starting tension is 30 pounds and the angle of arm 19 is measured clockwise from the horizontal through axis 20.

When the angle of arm 19 is 120, the starting force perpendicular to the arm at axis 14 is 23.88 pounds. The film tensions for various wind-up roll radii necessary to maintain the force at 23.88 pounds are as follows:

Radius in Tension in Inches Pounds Radius in Tension in Inches Pounds When the angle of arm 19 is 60, the starting force perpendicular to the arm at axis 14 is 48.69 pounds. The film tensions for various wind-up roll radii necessary to maintain the force at 48.69 pounds are as follows:

Radius in Tension in Inches Pounds To obtain substantially constant film tension the angle of arm 19 is set at 37.275 With this setting the initial film tension of 30 pounds produces a force of 51.13 pounds perpendicular to the arm at axis 14. The actual film tensions for various wind-up roll radii necessary to maintain the force at 51.13 pounds are as follows:

Radius in Tension in Inches Pounds While the tension obtained by setting arm 19 at 37.275 and maintaining constant the force perpendicular to said arm is not absolutely constant, it is substantially so. It may be observed from the above table that the maximum tension variation is only two percent with this arm setting. It will be apparent that tension variations for other arm settings may be readily obtained by the use of a computer or may be worked out graphically. Thus, a wide range of tension variations may be obtained by merely changing the location of guide roller 13 and with a construction such as indicated in FIG. 1 this repositioning of roller 13 is accomplished by swinging arm 19 about the axis While it is not normally desired to have an increasing strip tension, it is to be noted that with the present arrangement an increasing tension may be obtained by reducing the angle of arm 19 somewhat be low 37.275

The essence of this invention is that the strip tension is maintained at the level necessary to maintain constant the magnitude of the force tending to move roller 13 in a particular direction. In the embodiment shown diagrammatically in the drawing, the force tending to move roller 13 in the particular direction is the force perpendicular to arm 19 and such force acts on said arm at the axis 14 of the roller.

One way of obtaining such tensions will now be explained with reference particularly to FIGS. 2, 3 and 4. Shaft 20, to which arms 18 and 19 are secured, is rotatably mounted in a pair of bearings and 26 mounted in stationary supports 27 and 28 respectively. A counterweight 29 is secured to shaft 20 diametrically opposite roller 13 so as to olfset the weight of roller 13 and arms 18 and 19 when the roller is swung out of vertical alignment with the shaft. As shown in FIG. 2, shaft 20 extends through bearing 26 and the end thereof is of reduced diameter. A cup member 30 having an annular flange 31 is secured to the reduced diameter end of shaft 20. A member 32 having an outwardly directed arm 33, see FIG. 3, is loosely supported on shaft 20 adjacent cup member 30 and member 32. has an annular flange 34 extending over and around flange 31. The upper half of flange 34 is provided with inwardly directed teeth 35 and a toothed shoe 36 carried on a shaft 37 slidably mounted in flange 31 is urged by a spring 38 into engage ment with the teeth 35. The inner end of shaft 37 is provided with a handle 39 whereby the shoe 36 may be withdrawn from engagement with the teeth of flange 34 to permit shaft 20 to be rotated without transmitting its rotation to member 32 and arm 33 thereof. The free end of arm 33 rests on a support 40 so that said arm remains horizontal regardless of the rotated position of shaft 20. A pointer 41 is secured to arm 19 and said pointer moves over a scale 42 carried by hearing support 28. Scale 42 may be provided with indicia indicating degrees of rotation of arm 19 or other indicia indicating the amount of tension reduction to be obtained with a particular arm setting. In FIG. 3, 37.275 is indicated on the scale at 43, this being the arm setting to obtain substantially constant tension.

The strip tension force component which is perpen dicular to arm 19 tends to move said arm in a clockwise direction as viewed in FIGS. 3 and 4 and through the shoe 36 and toothed flange 34 the force is transmitted to arm 33. Slidably mounted on a stationary support 44 is a force sensing device or strain gauge 45 which may be of any desired commercial type, a proofing ring being shown in the drawing. One side of the proofing ring is in contact with arm 33 so that said ring senses the force on the arm. The proofing ring is electrically connected to a strain gauge recorder-controller 46 which indicates by a pointer 47 the force measured by the proofing ring. Recorder-controller 46 may be of any desired commercial type of which there are many.

Since the strain gauge is adjustable along the support 44 it may be so located that the arrow 47 of the recorder controller indicates on a scale 48 the actual strip tension at the start of the winding operation. As previously explained, a particular starting strip tension produces a particular force component perpendicular to arm 19 at the axis of roller 13, the magnitude of the component depending upon the angle of arm 19'. In the examples previously set forth, arm 19 is 10" long from the axis of roller 13 to the centerline of shaft 20 and when arm 19 is vertical, a starting strip tension of thirty pounds produces a force of thirty pounds perpendicular to arm 19 at the axis of roller 13. If strain gauge 45 is positioned on arm 33 ten inches from the axis of shaft 20 it will cause the recorder-controller to read thirty pounds. When arm 19 is set at 60, a starting tension of thirty pounds produces a force of 48.69 pounds perpendicular to arm 19 at the axis of roller 13. In order for the strain gauge to produce a reading of thirty pounds on the recorder-controller, said gauge will be positioned at adistance z from the axis of shaft 20 such that Arm 33 may be provided with a scale showing the settings for the strain gauge corresponding to the angular settings of arm 19 such that the recorder-controller will indicate the starting strip tension. These predetermined settings of the position of the strain gauge will be the same irrespective. of what the starting tension may be, inasmuch as the magnitude of the starting force perpendicular to arm 19 varies in direct proportion with the starting strip tension for all angular arrangements of the arm. This will be apparent from an inspection of the graph of FIG. 6, for example, where it may be noted that if the lines 23 and 24 are made half as long, the dashed lined resultant of these force lines will be half as long as shown and the distance between lines at and 19 will be half the distance shown. Thus, by proper positioning of proofing ring 45 along arm 33, the pointer 47 of the recorder-controller is caused to indicate the starting strip tension although the position of said pointer is actually determined by the force perpendicular to arm 19 as picked up by the proofing ring. After the position of pointer 47 has been observed, a set-point indicator 49 is moved to position of alignment with said pointer and the construction of the recorder-controller is such that the output thereof is continuously varied to the extent necessary to keep pointer 47 aligned with the set-point. The instrument 46 is electrically connected through a line 50 to the variable speed motor 16 which is drivingly connected through a chain or belt 51 to the Wind-up reel 15. As the force on the proofin g ring tends to increase due to the increasing diameter of the wind-up roll as aforesaid, the pointer 47 of the recorder-controller tends to move away from the set-point 49 but the instrument automatically varies the speed of motor 16 to the speed necessary to provide a strip tension which will keep constant the force on the proofing ring and thereby keep pointer 47 on the set-point.

While one preferred geometric arrangement of parts has been shown in FIG. 1, it will be apparent that essentially the invention comprises so locating a guide with respect to the wind-up roll that the resultant of the forces acting on the guide as a consequence of the tension in the strip has a component tending to move the guide in a particular direction which component force would in crease in magnitude as the diameter of the wind-up roll increased if the strip tension remained constant. Having provided such a geometric arrangement, the strip tension is then varied in such manner as to maintain constant the magnitude of the force tending to move the guide in the particular predetermined direction. Thus, guide roller 13, instead of being carried by the swingably mounted arms, could, for example, be mounted on a horizontally adjustable slide and the horizontal force on the slide could be used to control the strip tension. As previously mentioned, instead of using the recorder-controller to vary the speed of the wind-up roll it could be used to vary the speed at which the strip is supplied to the wind-up roll.

Having thus described the invention, what is claimed 1s:

1. In a controlled tension winding apparatus wherein strip material is wound onto a roll which increases in diameter as the winding operation proceeds, a winding reel for mounting the roll, variable speed drive means for said reel, guide means over which the strip material passes as it approaches said reel, a support for said guide means, pivot means mounting said support for swinging movement thereabout, means for latching said support in a plurality of swung positions about said pivot means to thereby locate said guide means in a plurality of positions in all of which the strip material makes a substantial change in direction as it passes thereover whereby the tension on the strip material produces a force perpendicular to said support which force, for any particular strip tension, increases as the diameter of the roll increases, sensing means for sensing the force perpendicular to said support, and means operated by said sensing means for operating said variable speed drive means to reduce the speed of said reel so as to maintain the tension in the strip material at the level necessary to keep constant the force perpendicular to said support.

2. In a winding apparatus wherein strip material is wound onto a roll which increases in diameter as the material becomes wound thereon whereby a constant r.p.m. of the roll would produce a constantly increasing tension in the strip; apparatus for controlling the strip tension comprising a reel supporting the roll, variable speed drive means for the reel, guide means over which the strip material passes as it approaches the roll, a support for said guide means, pivot means mounting said support for swinging movement thereabout, means for latching said support in a plurality of swung positions about said pivot means to thereby locate said guide means in a plurality of positions, the included angle between the line of approach of the strip material to said guide means and the line of movement of the strip material away from the guide means growing progressively smaller as the roll diameter increases whereby a constant tension on the strip material would produce a constantly increasing force perpendicular to said support, and means associated with said support and operable by the force perpendicular to said support to continuously reduce the speed of said reel as the roll diameter increases so as to maintain the tension in the strip material at the level necessary to maintain constant the force perpendicular to said support.

3. In a winding apparatus wherein strip material is wound onto a roll which increases in diameter as the material becomes wound thereon whereby a constant r.p.m. of the roll would produce a constantly increasing tension in the strip; apparatus for controlling the strip tension comprising a reel supporting the roll, variable speed drive means for the reel, guide means over which the strip material passes as it approaches the roll, a support for said guide means, pivot means mounting said support for swinging movement thereabout, means for latching said support in a plurality of swung positions about said pivot means to thereby locate said guide means in a plurality of positions, the included angle between the line of approach of the strip material to said guide means and the line of movement of the strip material away from the guide means growing progressively smaller as the roll diameter increases whereby a constant tension on the strip material would produce a constantly increasing force perpendicular to said support, a device associated with said support for sensing the magnitude of the 'force perpendicular to said support, and means operable by said device for causing said variably speed drive to continuously reduce the speed of said reel so as to maintain the tension in the strip material at the level necessary to maintain constant the magnitude of said force perpendicular to said support.

References Cited by the Examiner UNITED STATES PATENTS 2,586,037 2/52 Heffel finger.

3,031,152 4/62 Cohen et al 242-45551 3,060,357 10/62 Lohest 242- X FOREIGN PATENTS 710,263 6/ 54 Great Britain. 871,763 6/61 Great Britain.

MERVIN STEIN, Primary Examiner. 

1. IN A CONTROLLED TENSION WINDING APPARATUS WHEREIN STRIP MATERIAL IS WOUND ONTO A ROLL WHICH INCREASES IN DIAMETER AS THE WINDING OPERATION PROCEEDS, A WINDING REEL FOR MOUNTING THE ROLL, VARIABLE SPEED DRIVE MEANS FOR SAID REEL, GUIDE MEANS OVER WHICH THE STRIP MATERIAL PASSES AS IT APPROACHES SAID REEL, A SUPPORT FOR SAID GUIDE MEANS, PIVOT MEANS MOUNTING SAID SUPPORT FOR SWINGING MOVEMENT THEREABOUT, MEANS FOR LATCHING SAID SUPPORT IN A PLURALITY OF SWUNG POSITIONS ABOUT SAID PIVOT MEANS TO THEREBY LOCATE SAID GUIDE MEANS IN A PLURALITY OF POSITIONS IN ALL OF WHICH THE STRIP MATERIAL MAKES A SUBSTANTIAL CHANGER IN DIRECTION AS IT PASSES THEREOVER WHEREBY THE TENSION ON THE STRIP MATERIAL PRODUCES A FORCE PERPENDICULAR TO SAID SUPPORT WHICH FORCE, FOR ANY PARTICULAR STRIP TENSION, INCREASES AS THE DIAMETER OF THE ROLL INCREASES, SENSING MEANS FOR SENSING THE FORCEPERPENDICULAR TO SAID SUPPORT, AND MEANS OPERATED BY SAID SENSING MEANS FOR OPERATING SAID VARIABLE SPEED DRIVE MEANS TO REDUCE THE SPEED OF SAID REEL SO AS TO MAINTAIN THE TENSION IN THE STRIP MATERIAL AT THE LEVEL NECCESSARY TO KEEP CONSTANT THE FORCE PERPENDICULAR TO SAID SUPPORT. 